You can find it online at HiTimeWine.net
I have ordered from them in the past and they are a good online outlet. Sometimes they are out of good deals they list online but everyone plays that game from time to time I have found.
But watch out, there are 2 different bottlings of BMH out there done by 2 different people. The first release was done by Julian Van Winkle and included a 14, 16, 18 and 20yo bourbon and a 15yo rye. The new releases include the 11, 16, 21 and I think something like a 18yo rye(?). If I recall correctly they may have been done by the Kulsveens, but please correct me if I am wrong...
I have heard very good things about the first releases done by Julian and people who I know tried the new 16yo liked it as well... I have not tried them yet, but hope to try the new ones soon. If you want to see pics of all 5 of the original ones done by Julian search for them in the database (whiskey reviews link at the top), we added pics and proofs for all of them.